Hitchcock liked to play with Freudian symbolism. Even so, he'd probably be surprised at some of the interpretations of Jeff's full-leg cast. Just as it makes Jeff powerless to get around or do anything, it's seen by many critics as a symbol of sexual impotence. Stella has already made some wisecracks about Jeff's lack of sexual interest in the bathing beauties he's been watching from the window—they haven't raised his temperature a bit. She jokes that he must have a "hormone deficiency."

She's also wondering why he hasn't jumped at the chance to marry the beautiful Lisa. Maybe it's a fear of being tied down. Roger Ebert's take? "But perhaps his real reason for keeping her away is fear of impotence, symbolized by the leg cast." (Source) And how about this: "[…] Jeff's cast is a phallic symbol—long, stiff, and jutting from the body. Yet the cast also signifies that something is broken, weak; as Modleski writes, [it's] a physical impotence, but also a sexual one." (Source) Whether you buy it or not, it's true that Lisa is the one initiating all of the sexual activity in the film. Jeff seems totally uninterested in her.

In the last scene, Jeff has casts on both legs—"doubly castrated," according to Filmsite. Lisa lounges around wearing jeans and loafers—she's now wearing the pants in the family, so to speak, while Jeff sleeps like a baby.